Very weak brakes

[Mike Grevers]

I am a new owner of a 2003 Beaver Patriot Thunder 505. This coach has not been registered since 2007. I had it towed to my home and got the engine running. I got new tires installed and on the drive to and from the tire shop I noticed extremely hard breaking (as in very difficult to get the coach to stop). I was able to get most of the way home when I noticed excessive smoke from the drive axle. I immediately pulled over and checked the rear brakes. They had both locked up on the drive axle. I proceeded to get underneath and with a small sledge hammer beat the actuators into the unlocked position. I was then able to drive the last mile to my home with still very hard breaking. I removed both drive axle wheels and thoroughly greased every point that I could find and that it showed in the owners manuals. I loosened the slack adjusters on the drive axle slightly (1/2 turn) and was able to spin the wheel with the brake released. I then put the wheels back on greased the front end as well and tried the coach. Now i have almost no brakes at all. Mind you I did not adjust any of the brakes other than the drive axle. I have 120 PSI air pressure on the dash. I also have the ABS light on.

My questions is this. Where should I start. I don't really want to take every last brake component apart as it is not fun laying under the bus. I am thinking of starting with the relay valves as the most likely culprit and maybe pulling an actuator or two to make sure that the S cams move freely. Is there anyone else that has had a loss of brakes on a coach that has been sitting for some time? and if so what was your solution? With an ABS light on will that keep the brakes from actuating properly? If so that would be a pretty bad design if you had a bad sensor and therefore couldn't stop.

Thanks for the help.

[Fred Cook]

 Wow! Are you saying that this coach has been sitting for 12 years?  If you have the Meritor brakes it needs to be greased with a clay-based grease. Otherwise the brakes will burn up.  You may want to take it to a chassis shop with a good reputation for a thorough check up. That is a long time to be sitting.  Hope it all works out for you and welcome to the forum!

[Eric Maclean]

Hi Mike
 your brake issues could be one of many things in the system but an ABS light is an indication of an electronic problem with in the ABS circuitry ( the system it self has recognized a problem in it's operation) IE a wheel speed sensor failure ,modulator valve failure etc
if you have an ABS lamp on you have an associated trouble code in the computer which will point you in the right direction.
As for the ABS system causing a lack of or no braking this is not likely the fault of the ABS. Most ABS systems shut down when a fault code is logged at any rate the foundation brakes are at the very least not releasing the rear brakes you spoke about S cams so I will assume we are working with drum brakeshere are a few things to check
the vehicle has sat for an extended period of time so we will have to visit the foundation brakes (this is the basic drums ,shoes,S cams ,
brake Chambers and yes the relay and Quick Release valves
with out pulling wheels to check the shoes and drums look closely at the rear backing plates for signs of gear oil from the rear inner axle seals (may have dried up and are possibly leaking onto the shoes and drums
second the brake chamber clevis pins ( where the chamber rods connect to the slack adjuster) will  some times seize in the slack adjuster  causing the brake to to remain applied the pins should turn freely with the spring brakes released ( remember to block wheels  and chassis before going under coach)
Also check the S cam bushings a seize bushing here can cause a brake to drag or not apply as well.
with spring brakes released adjust the slack adjuster to stop the wheel not overly tight but just until the adjuster stops then depending on which type of slack adjusters you have there will be ratchet paul on some that must be released to turn the adjuster bad from the applied position  Turn the adjuster back half a turn this is you final adjustment. With this done we can assume your foundation brakes are correct and move on to air operation check your treadle valve they get corroded at the hinge point and can stick in the apply position.
now have someone release the spring brakes and listen for air leaks (bad diaphragm)
if no leaks are head have them apply the service brake and listen again for leaks ( bad service diaphragm)
look at the slack adjusters as the brakes are applied you should get approx one and a half inches of travel and they should the QR valve should release a puff of air as the brakes are released a9 be sure the slack adjusters all return to rest
if these checks are all ok the apply pressures are suspect your system will have relay valves and ABS modulator valves which control individual wheels ( unlikely these are at fault as they is one for each wheel and the odds of two being fault at the same time is remote)
as we work our way back up the system we have relay valves and the treadle valve  itself ( which is what modulates apply pressure)
hope some of this rambling is of some use to you
Good luck Eric
   

[Mike Grevers]

Thank you guys for the suggestions. I did already have the drive axle wheels/drums off. The brakes are dry but I believe that my issues likely are in the s-cams themselves. I thought that possibly the actuators are sticking but that seems unlikely. I plan to remove all of the wheels and drums this weekend. I will remove all of the pins and see if the s-cams move freely. If not I will remove the S cams and repair or replace them. Like Eric said the chances of anything else going bad on every wheel is unlikely. My brake shoes currently say Spicer on them. When I look up Spicer brake shoes I get results for Meritor. Does Spicer make Meritor? Can S cams be dissembled and cleaned/repaired? The coach only has 32,000 miles on it so I doubt that they are worn out but likely just stuck from sitting for years. I will update with what I find.

Thanks,
Mike

[Mike Shumack]

On the year coach, you should have drum brakes on front and rear.

If you have front disc brakes they would be the ESD-225 (no lubrication points).

The Drum brakes in the front are Bendix ES 150-4L or EB 150-4L.

All of the old (in my mind) heavy truck parts manufacturers are now merged (Dana-Spicer, Bendix-Meritor-Wabco, etc.)

[Eric Maclean]

Hi Mike
the S cams can be removed by removing the snap ring at the end of the shaft and removing the slack adjuster (they may be tight on the shaft and require a puller to remove them)
the S cam should pull straight out
the S cam bushings are not precision fitted don;t be alarmed if they seam sloppy.
 I have installed new S cams and the plastic bushings they rotate on and ended up with 1/16 to 1/4 of up and down movement. 
At any rate the slop does not effect the operation of the brake itself.

There should be grease fittings on the S cam bushings
I have had good results by removing the S cam rollers from the shoes and removing the upper return springs turning the shoes out away from the S cam and then rotate the slack adjuster adjustment  while greasing the bushings this will rotate the S cam through a full rotation and lube and exercise the shaft freeing them up.

while we are on the subject to identify a seized S cam try loosening the brake adjustment if the S cam or clevis pin is seized the slack adjuster will try to pull the brake chamber rod out of the chamber against the spring tension

Don;t be afraid of them those drum foundation brakes are almost the same as a 1928 Ford Model A
good luck
Eric

 

[Mike Grevers]

Thanks for the help. I ended up having to replace all of the clevis pins. The S cams moved freely by hand on the steer and tag axles. They where a little tougher to move on the drive axle but where a completely different cam. I got it back together and set the slack adjusters as everyone said above. The brakes feel good and release well. I hope that after a few hundred miles of use that the cams free up with the new grease and the brakes get even smoother. I am very impressed with the way that this coach is built and how much works after sitting for more than 10 years. I have a few other issues to sort through but its good to know there is a lot of knowledge on this forum.

Thanks again.

[David T. Richelderfer]

Another event that can cause weak braking is overuse resulting overheating on the face of the brake pads causing the surface of the brake pads to glaze.  I would think this could happen more on drum brakes versus disk brakes.  I remember when growing up on the farm, dad warned that when going downhill with a full load of wheat, we had to slow way down to get the engine to provide much of the braking rather than depending on the brakes too much.  Once the brake pads get glazed, they will provide little braking.  Perhaps someone overused the brakes in prior years.  Just a thought...